| Name | School | Sub-Type |
|---|---|---|
| International Boosters | Classification 1 | |
| International PTSA | Classification 1 | |
| International School Student | ||
| Issaquah Dance Theatre | ||
| Issaquah Tennis | ||
| JET USA | Classification 3 | |
| JR7 Soccer | Bellevue High School | |
| Jay Hawblitzel basketball | Classification 2 | |
| Jazz Choir | Chinook Middle School | |
| Johns Hopkins University | ||
| Jr. Wolverine Football | ||
| Jubilee Reach Sports | ||
| Junior American Literature Team | ||
| Just Ice | ||
| KCLS Teen Services Outreach Branch | ||
| KINGCO FALL COACHES | Newport High School | |
| KINGCO Tennis Seeding | ||
| Kalapriya School of Performing Arts | ||
| Kannada Bharati | ||
| Kerala Assn of Washington (KAW) | Classification 3 | |
| Kids Academic Lab | ||
| King County 4-H | ||
| King County Democrats | Classification 3 | |
| King County Republican Party | Classification 3 | |
| KingCo | ||
| Kirkland Dance Center | Classification 2 | |
| Kodu Game Lab -- Main Stem Academy | ||
| LAKE WA DENTAL HYGIENISTS | ||
| LIGHTHOUSE CHRISTIAN CHURCH | Classification 3 | |
| LaVida Studio | Classification 3 |
